Field of the Invention
The present disclosure relates to a light emitting device.
Description of the Related Art
A light emitting device capable of emitting white light has been developed by combining an LED (Light Emitting Diode) as a light emitting element that emits blue light with a fluorescent material that is excited by the blue light and emits green light and a fluorescent material that emits red light. For example, JP 2008-303331A describes a nitride or an oxynitride having a β-type Si3N4 crystalline structure (a β sialon fluorescent material), which is a fluorescent material that emits green light. JP 2008-303331A also describes a light emitting device that includes the green fluorescent material, a red fluorescent material (CaSiAlN3:Eu), and a blue LED, and that emits white light. The white light is obtained by exciting the green and red fluorescent materials with the blue LED, thereby mixing light from the LED and the fluorescent materials.
Furthermore, JP 2007-027796A describes a light emitting device including a light emitting element that emits blue light, a fluorescent material that is excited by the blue light and emits green light ((Sr,Ba)2SiO4:Eu), and a fluorescent material that emits red light (CaAlSiN3:Eu). The peak wavelength of the (Sr,Ba)2SiO4:Eu fluorescent material may be adjusted within the range of from 520 nm to 600 nm. This permits control of the range of color reproduction, resulting in a wide range of color reproduction.
As a related art focusing on the color reproducibility (NTSC (National Television System Committee) ratio) of a liquid crystal display (LCD), for example, JP2003-121838A describes a liquid crystal display that includes a backlight light source having a spectral peak in the range of from 505 nm to 535 nm. The backlight light source includes a green fluorescent material such as MgGa2O4:Mn and Zn2SiO4:Mn, containing any one of europium, tungsten, tin, antimony, and manganese, as an activator.